电工电子学课后答案

1-1

S断开：I=1A,Uab=8V;

S闭合：I=1.67A,Uab=6.67V

1-2Uab=14V1-3

(a)IR+Us+U=0 (b)IR-Us+U=0(c)-IR+Us+U=0 (d)IR+Us-U=0

1-4A、B是电源，C是负载1-5UA=-4V1-6

UA=11V

1-7I=-0.5A1-8I=1.2A1-9

I=-1A

Iab=-2AI=4AR=50Ω

I1=2A,I2=-0.5A,I3=-1.5AI=1A

2-1

2-2

2-3

2-4

2-52-6

2-7

2-82-9

2-10

2-112-122-13

1-101-111-121-131-14

1-151-161-171-181-191-201-211-22

I=0U=36VU=36V

UA=-14.3V;UA=5.45VI=2AI=-1A

I=2A,方向B到ARL=Ro=4Ω，PMAX=1W

习题答案

i L ( 0 ) 1A, i( 0 ) 3 A, i s ( 0 ) 2 A, u L ( 0 ) 4V

3-1

i1(0 ) 3 A, i2(0 ) 2.4 A, i3(0 ) 1.2 A, u c (0 ) 4.8V

3-2

2 10 6 S3-3

0 . 25 S3-4

u c ( t ) 8 4 e 37 .5 Vi 0.5 0.1e t A u c (120 80e 1000t )V

3-5 3-6

3-7

u c 60e 11tV , i1 12e 100t mA

3-8 3-9

i1 2 e 2t A, i 2 3 2e 2t A, iL 5 3e 2t A

uc 8 6e

1 108 t 3

V , iL e

4t

At

u AB

3 9 7.5(1 e )V , i ( e 5 ) A 4 4

t 5

3-10

3-11i(t ) 5 5e 2t Au c ( tb) 4.325V

3-12 3-13 3-14

习题答案

iL(0 ) 1A,i(0 ) 3A,is(0 ) 2A,uL(0 ) 4V

i1(0 ) 3A,i2(0 ) 2.4A,i3(0 ) 1.2A,uc(0 ) 4.8V

2 10 6S

0.25S

u 37.5c(t) 8 4eV

i 0.5 0.1e tA

u 1000tc

(120 80e)V

uc 60e 11tV,i1 12e 100tmA

i(t) 5 5e 2tAuc(tb) 4.325V

3-1

3-2

3-3

3-4

3-53-6

3-7

3-83-9

3-10

3-11

3-123-133-14

3-153-163-173-183-193-20

I

5 30

AU

145 165

A

I

7 125

Au

10 30 A

u 220sin( t 30 )V,i 5sin( t 143 )A,i 5sin( t 37 )A

I

0.45 0 A,R 484 ,W 1度

f 50H

Z,I 28 30 AQL 6154Varf 500H

Z,I 0.28 30

AQL 61.54Var

f 50H

Z,I 0.69 90 AQL 152Varf 500HZ,

I

6.9 90 A

QL 1520Var

L 0.01H,S 2400VA,QL 1328Var,cos 0.83

(1)U 298V,I 4A,UAB 168V

(2)cos 0.84,P 1005W,Q 640Var,S 1192VA

r 1.6 ,L 15mH

亮度相同，连接电感灯泡亮度最亮，连接电阻的灯泡较暗，连接电容的灯泡不亮

I

0.37 60

A,U

R 103.6 60,UrL 192.5 27.8 ,P 41.07W,Q 71.19Var,S 81.4VA

V表：U 220V，A1表：I1 15.56A,A2表：I2 11A,A表：I 11A,R 10 ,L 31.8mH,C 159 F

I

L

6 90 A,I

I

R 8 0 ,C 12 90 ,I 10 37 A,cos 0.8,

P 960W,Q 720Var,S 1200VA

I1 9.38A,I2 4.12A,I 9.71A,cos 0.97,P 1131.3W,Q 279.3Var,S 1165.2VA应接入串联谐振电路

4-1

4-2

4-3

4-4

4-54-6

4-7

4-84-9

UAB=5VU AB 81.6 20 V,U 83.3 17.4 V, I C 2.04 110 A, I 2.06 46 A cos 0.45,P 77. W,Q 153.5Var,S 171.5VA 1

I 10 A U 100 2 V

U 5 63.4 V,A,I 0.707 45 A cos 0.95,P 1.5W,Q 0.5Va

r,S 1.58VAC 168 F (1) cos 0.5(2)c 102 F

UAB=5V

UAB 81.6 20V,U 83.3 17.4V,IC 2.04 110A,I 2.06 46 Acos 0.45,P 77.1W,Q 153.5Var,S 171.5VA

I A I B I C 11A, i A 11 2 sin( t 30 ) A i B 11 2 sin( t 150 ) A, iC 11 2 sin( t 90 ) A(1)U P 220V , I A 20 A, I B I C 10 A, I o 10 A, ( 2)U A 0V , U B U C 380V , I B I C 17.3 A, I A 30 A (3)U Co 335 100 V

(1)i A 22 2 sin( 314t 30 ) A,i B 22 2 sin( 314t 120 ) A iC 22 2 sin( 314t 180 ) A (2)P PA I A R 4840W,PB PC 02

(1) I AB 22 60 A, I A 38 30 A, (2) I A 22 0 A

(1)两种连接线电流相等，Il=6.1A, P1=3089.868W,P2=1783.884W I=32A

(1) I AB 57 A, I BC I CA 33 A, P 43 .45 KW , I A 65 .8 30 A I B 65 .8 150 A, I C 65 .8 90 A ( 2 ) I BC I CA 19 180 A, I AB 57 0 A, P 28 .9 KWI 1 6873.42 A, S 1.25 10 5 KVA, Q 0.75 10 5 KVar

(1) A1 , A2 表读数2.2A,A3 表读数3.8A (2) A1 , A3 表读数3.3A,A2 表读数0A

(1)UP 220V,IA 20A,IB IC 10A,Io 10A,(2)UA 0V,UB UC 380V,IB IC 17.3A,IA 30A(3)UCo 335 100 V

(1)IAB 22 60 A,IA 38 30 A,(2)IA 22 0 A

(1)两种连接线电流相等，Il=6.1A,P1=3089.868W,P2=1783.884W

I=32A

(1)IAB 57A,IBC ICA 33A,P 43.45KW,IA 65.8 30 AIB 65.8 150A,IC 65.8 90 A

(2)IBC ICA 19 180A,IAB 57 0 A,P 28.9KWI1 6873.42A,S 1.25 105KVA,Q 0.75 105KVar

(1)A1,A

2表读数2.2A，A3表读数3.8A(2)A1,A3表读数3.3A，A2表读数0A